More abilities

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/Illusion.cs

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+namespace PkmnLib.Plugin.Gen7.Scripts.Abilities;
+
+/// <summary>
+/// Illusion is an ability that disguises the Pokémon as the last non-fainted Pokémon in the party until it takes damage.
+///
+/// <see href="https://bulbapedia.bulbagarden.net/wiki/Illusion_(Ability)">Bulbapedia - Illusion</see>
+/// </summary>
+[Script(ScriptCategory.Ability, "illusion")]
+public class Illusion : Script
+{
+    private IPokemon? _pokemon;
+
+    /// <inheritdoc />
+    public override void OnAddedToParent(IScriptSource source)
+    {
+        if (source is not IPokemon pokemon)
+            throw new InvalidOperationException("Illusion can only be added to a Pokemon script source.");
+        _pokemon = pokemon;
+    }
+
+    /// <inheritdoc />
+    public override void OnSwitchIn(IPokemon pokemon, byte position)
+    {
+        var battleData = pokemon.BattleData;
+        if (battleData is null)
+            return;
+        var lastNonFaintedPokemon = battleData.Battle.Parties.FirstOrDefault(p => p.Party.Any(pkmn => pkmn == pokemon))
+            ?.Party.WhereNotNull().FirstOrDefault(x => x.IsUsable);
+        if (lastNonFaintedPokemon is null || lastNonFaintedPokemon == pokemon)
+            return;
+
+        pokemon.SetDisplaySpecies(lastNonFaintedPokemon.Species, lastNonFaintedPokemon.Form);
+    }
+
+    /// <inheritdoc />
+    public override void OnRemove()
+    {
+        if (_pokemon is null)
+            return;
+
+        _pokemon.SetDisplaySpecies(null, null);
+        _pokemon.BattleData?.Battle.EventHook.Invoke(new AbilityTriggerEvent(_pokemon));
+    }
+
+    /// <inheritdoc />
+    public override void OnIncomingHit(IExecutingMove move, IPokemon target, byte hit)
+    {
+        if (_pokemon?.BattleData?.Battle is null)
+            return;
+
+        // Remove the illusion when the Pokémon takes damage
+        _pokemon.SetDisplaySpecies(null, null);
+        _pokemon.BattleData.Battle.EventHook.Invoke(new AbilityTriggerEvent(_pokemon));
+    }
+}